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KG7PFS

All I want is a monitor

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AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

It seems like such a simple thing. A clear picture. 80 collum mode in color. Analog color, not rounded off to the nearest CGA equivalent. Sharp text, not blurry.

 

No. The CoCo 3's plain, simple, analog RGBHV is just too stinking simple. Everyone else has to complicate the living daylights out of their monitor. Composite sync. Sync on green. Sync on blue. Sync on the wazoo. 48khz sync.

 

TV gets a lousy picture. Composite gets a lousy picture. CGA gets a lousy picture. VGA with the Microbee RGB to VGA converter is almost as bad as composite.

 

Is there anyone in the whole stinking lousy world who can see what their doing on a Tandy Color Computer 3?

 

HEEEEEELLP!!!

 

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27 minutes ago, towmater said:

Scart to hdmi works for me.

 

The CoCo 3 doesn't have SCART.

 

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3 hours ago, KG7PFS said:

The CoCo 3 doesn't have SCART.

 

It's a cable that plugs into the bottom.  They are fairly common, look for one with a usb power supply to be certain your hdmi converter will go into RGB mode.

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Coco3 is really sharp on its rgb monitor , the composite really sucks though.. cocoman.biz sells a rgb to scart cable that you can hookup a scart to hdmi wire to.. its not hard to make if you like doing that,, also zipster will have his coco gimex with vga hookup ready for general public soon..

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So I'm supposed to blow a big wad of money on an adapter to convert the Coco's ultra-standard RGBHV (so perfectly standard it makes everything else non-standard) to a weird "standard" that has never been used anywhere on anything by anyone, just so I can blow another big wad of money to convert that to something standard.

 

Regarding Zipster's VGA converter, I already got a VGA converter from Microbee. I think it's as bad as composite, but today I'll hook up my Commodore 1701 and see if it's any better or worse.

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Im not talking about a vga converter.. this is a graphics chip replacement that outputs true vga 

There is a thread somewhere here about this..i use a cm 8 monitor on my coco3 its a very clear rgb but i will get the new vga hookup

Screenshot_20201115-175527_Chrome.jpg

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On 11/15/2020 at 1:12 PM, KG7PFS said:

So I'm supposed to blow a big wad of money on an adapter to convert the Coco's ultra-standard RGBHV (so perfectly standard it makes everything else non-standard) to a weird "standard" that has never been used anywhere on anything by anyone, just so I can blow another big wad of money to convert that to something standard.

 

Regarding Zipster's VGA converter, I already got a VGA converter from Microbee. I think it's as bad as composite, but today I'll hook up my Commodore 1701 and see if it's any better or worse.

I just ran into this thread and had to comment - SCART isn't a weird standard that no-one uses, or at least it wasn't in Europe back in the day, though as far as I know, the US didn't pick it up or at least not under the same name (see the wikipedia link below). It was the standard used to connect pretty well every TV to video recorder or DVD player back in the 90's. My parents' cable box had it too. Is far as I know, SCART is really just the connection, not the data standard. It had 21 pins and output composite, RGB and S-video, so there is a good chance that the adapter you guys are discussing doesn't actually change the signal in any way, just puts it through a different connector.

 

SCART - Wikipedia

 

 

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I don't know about European standards. They are irrelevant in the United States because European TV's are not sold here. Not that I'm not interested in European, Austrailian or Japanese computers, but I need a monitor that's compatible with *this* American computer. No American TV, VCR, or DVD player has ever had a "SCART" connector. Buying multiple converters gets expensive after a while, so converting from American to foreign, to extraterestrial, to ultraterestrial standards, just so I can change it all back, is something I hope to put off as log as possible.

 

According to some roumors, there is a composite sync signal somwhere inside the CC3. Finding it will help but I'll need to modify connectors or something. Don't some RGB outputs have composite sync on the horizonal pin? How incompatible would that be? Does anyone know how complex a composite sync on green mod would be?

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Coco3 has a rgb connector underneath, Composite video (red rca) , and mono audio out(white rca) and a rf out on rca ..the composite out does not look great on lcd screens though.. but is not bad for games.

The reason to convert to scart if because scart to hdmi is a easy to find converter and cables to go from cocorgb to scart are easy to make or purchace . 

 

 

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What about one of these - looks pretty flexible in terms of the inputs it accepts. It’s designed to allow old video arcade games to be converted to work with modern monitors, so there’s a good chance it will work with a CoCo3 too. They are around $37 on e-bay, but more info was provided on Amazon, so I reproduced one of the versions available there. 

ECD330BE-0041-4F53-8241-BBAA1B75B0EB.png

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I have one. All by itself, it doesn't work. No vertical sync. The Microbee converter adds another little board and puts them in a nice case. The quality is no better than composite.

 

I sure wish there was someone here who could tell me how to do a composite sync on green mod. It seems like that would be so simple. Then I could use the Apple monitor I have.

 

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On 12/22/2020 at 11:52 AM, KG7PFS said:

I don't know about European standards. They are irrelevant in the United States because European TV's are not sold here. Not that I'm not interested in European, Austrailian or Japanese computers, but I need a monitor that's compatible with *this* American computer. No American TV, VCR, or DVD player has ever had a "SCART" connector. Buying multiple converters gets expensive after a while, so converting from American to foreign, to extraterestrial, to ultraterestrial standards, just so I can change it all back, is something I hope to put off as log as possible.

I have one of the RGB to SCART adapters and a stupid cheap SCART to HDMI converter. I'm an American, and I use it for the CoCo3 and it works *just fine* and gives a beautiful display on the CoCo3.

 

This would be your easiest way to hook a CoCo3 up to a modern display.

 

Also works great for an Atari ST and a ZX Spectrum and other machines.

 

There are also SCART switches out there you can get on eBay or whatever, so you don't need tons of extra converters. I have a Hydra from Lotharek for that purpose.

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I don't want a modern display. I like the look of the picture tube these computers were meant to use. I have and Apple RGB monitor. A composite sync on green mod should be fairly simple, (I hope) and would solve a lot of peoples problems.

 

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1 hour ago, KG7PFS said:

I don't want a modern display. I like the look of the picture tube these computers were meant to use. I have and Apple RGB monitor. A composite sync on green mod should be fairly simple, (I hope) and would solve a lot of peoples problems.

 

I always liked the larger text modes for that reason,

 

Using RF and a classic Television is very clear with artifact color support over NTSC.

 

The CoCo III can also do some really interesting demo's in the older graphics modes:

    Impossible TaffyBall and Revolving Balls CoCo Demo - Tandy Computers - AtariAge Forums

 

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6 minutes ago, Mr SQL said:

I always liked the larger text modes for that reason,

 

Using RF and a classic Television is very clear with artifact color support over NTSC.

 

If I could live without 80-collum mode I would, and I wouldn't be here whining and irritating you, but the CC3 has it, so some software requires it. I've noticed that late '90's tvs have verry good pictures on the Commodore, Atari, and CC3 except in 80 collum mode.

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1 hour ago, KG7PFS said:

I've noticed that late '90's tvs have very good pictures on the Commodore, Atari, and CC3 except in 80 column mode.

 

I like CRT's too.  

 

Yeah, I have a CC3 myself.  With composite, and 80 column, the better the CRT circuits are, the WORSE the CC3 display actually is!  For a long time, I ran my CC3 on a Zenith 80's era TV, and that one didn't have the advanced filtering newer sets do.  It worked pretty well.  Black on green is pretty brutal, given how the CC3 outputs video in the first place, but on the other hand, how it outputs video makes for spiffy 8 bit / pixel graphics on an NTSC set too, so...

 

What I do with mine, when running composite, is chain in a little monochrome Amber screen.  Works great, but being sharp, again that black on green is brutal.  I usually change it to something without color, white on black, black on white, or put one of the greys in there.  For programming, this works!  Not all software offers the options though.

 

I got a nice PVM to game and compute on sometimes.  It does odd things with both a CC3 and my Apple 2.  Fortunately, 80 column on the Apple is just monochrome, so it's no big deal.  

 

Atari and C64 offer up better signals, and a non-composite option.  Those look pretty great, as does anything with phase change color signals.  

 

To sum up, the circuits got better than the old machines video to a fault!

 

My PVM will take a CC3 signal directly due to it having an option for composite sync and separate.  I can just press an input button to switch between composite and RGB, and it all just works.

 

I don't have anything to test this circuit with, but what's shown above has the current limiting needed to be pretty harmless.  Bet it works.

 

:D

 

Edited by potatohead
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Thanks for the circut, I'll be ordering parts soon! That's exactly what I needed!

 

What's a PVM?

 

Edited by KG7PFS

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It's one of those pro grade CRT displays.  A BVM is a broadcast grade one.

 

They will work at 15Khz, offer a range of inputs and typically have great circuits and geometry.  The better ones offer fine pitch CRT tubes, and that's true of the one I got.  It's basically an XVGA grade CRT running in an NTSC / PAL monitor.  The fine pitch means being able to display monochrome up to somewhere around 600 lines without the fringing seen on more coarse pitch CRT's typically used for consumer grade watching.

 

The one I have has separate sync, RGB input.  Basically can hook a CC3 or GS right up to it and go.  It's either the 1342 or 1344Q, and I have to look at the back to be sure.  Both are the same, except one has component input YCb,Cr, and the other has digital TTL, like CGA type, and I've got the digital TTL one.  At some point, I want an older DOS PC, so this display is basically ready to go there.  

 

In terms of signals, if it's standard definition, this display will display it.  Got it before the CRT craze for a song.  It's a few hundred to score now.  That blew up quick!

 

If you get lucky and or want to get one of these, they are great!  If you are going to spend for one, get the fine pitch tubes.  Often, the same display will be branded normally, or say something to the effect of "fine pitch" or "super", and those are the ones with great CRT tubes in them.  Or...  not.  The standard pitch displays are still awesome.

 

 

 

 

Edited by potatohead

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9 minutes ago, KG7PFS said:

Thanks for the circut, I'll be ordering parts soon! That's exactly what I needed!

I'm glad it was still online.  Recall seeing it years ago.  The nice thing about that circuit is it is passive.  Runs on the signal itself and does not require external power.  Handy dandy.

 

 

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1 hour ago, KG7PFS said:

If I could live without 80-collum mode I would, and I wouldn't be here whining and irritating you, but the CC3 has it, so some software requires it. I've noticed that late '90's tvs have verry good pictures on the Commodore, Atari, and CC3 except in 80 collum mode.

Gotcha, the reason for that is that TV cannot display 640 pixels horizontally clearly (80 column text), so it looks a little fuzzy at best.

22 minutes ago, potatohead said:

What I do with mine, when running composite, is chain in a little monochrome Amber screen.

X2 - I brought Orange and BW monitors to RainbowFest for my company in addition to Color CRT just for that reason, it's a little clearer resolution.

Orange Worked better for text adventures, 80 column mode, and for the PageMaker desktop publishing clone using standard NTSC composite.

 

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11 minutes ago, Mr SQL said:

Gotcha, the reason for that is that TV cannot display 640 pixels horizontally clearly (80 column text), so it looks a little fuzzy at best.

Some of that has to do with the CRT in the TV.  Frankly, many ordinary consumer grade sets will display a monochrome, composite signal better than you think when equipped with a better CRT.

 

The PVM I have does it easily, over composite or S-video.  And when it's monochrome, it works in the 600 lines range.  That's still 2/3 what the little amber screen will do.  That one exceeds 800.

 

That's basically what a PVM is.  Now, most of those offer better, wider bandwidth circuits too.  But, since the 90's, most TV circuits are more than good enough.  Swapping out a CRT is a PITA though.  I've done it multiple times in the past, and actually the first time was as a kid!  Wanted a full frame display for my Atari to see all the overscan action.  The new tube was a bit smaller, but had basically half the pitch of the one in the set.  The difference was clear, and that one could display 80 columns!  Was a Zenith that I did a full realignment on.  

 

And that's the other thing true after the 90's.  Circuits stayed aligned far better than they did before.  Older era TV's would degrade fairly rapidly.  Component values changing, etc...  An afternoon spent redoing everything would result in a great picture for another year or maybe two.  Used to do that, using my Atari for signals and patterns, for date money.  LOL.

 

 

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On 12/22/2020 at 2:52 PM, KG7PFS said:

I don't know about European standards. They are irrelevant in the United States because European TV's are not sold here. Not that I'm not interested in European, Austrailian or Japanese computers, but I need a monitor that's compatible with *this* American computer. No American TV, VCR, or DVD player has ever had a "SCART" connector. Buying multiple converters gets expensive after a while, so converting from American to foreign, to extraterestrial, to ultraterestrial standards, just so I can change it all back, is something I hope to put off as log as possible.

 

According to some roumors, there is a composite sync signal somwhere inside the CC3. Finding it will help but I'll need to modify connectors or something. Don't some RGB outputs have composite sync on the horizonal pin? How incompatible would that be? Does anyone know how complex a composite sync on green mod would be?

There has to be composite sync on the composite output on the back (the middle 'pin', I think), right? so worst case, you could rig a cable that connects to both the RGB underneath and the composite sync from the back into a single cable and run that to your monitor. As a more visually appealing alternative, you could run a bodge wire from the composite connector to the spare pin (10) on the RGB out, and then you should have what you need coming out of the RGB port, and you can built a cable that connects from there to your monitor. I think this is right, can anyone confirm?

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The sync is there, but so is the signal.  Also, just wiring them together may damage either the monitor and or computer too.

 

Direct coupling may create a circuit path and deliver current where neither device expects it.

 

All that said, doing that may work, depending on the sync levels and how well the display would reject the composite signal coming along for the ride.

 

Sync being on the green pin means anything other than sync combined wit it is likely going to show up on the display, IMHO.

 

If there is a sync only source on the computer, a resistor and capacitor may decouple it from DC current and or set the sync level to an appropriate one for the display.  That is basically what the circuit above does.

 

The transistor is in there to combine separate sync.

 

 

 

 

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